Atrial pocket closures for prosthetic heart valves

ABSTRACT

A prosthetic heart valve can include an outer frame coupled to an inner frame such that the outer frame can be moved between a first position and a second position in which the outer frame is inverted relative to the inner frame. The inner frame and the outer frame define between them an annular space, and a pocket closure can bound the annular space to form a pocket in which thrombus can form and be retained. The pocket closure can include a stretchable pocket covering that can move from a first position in which the pocket covering has a first length when the outer frame is in the first position relative to the inner frame and a second position in which the pocket covering has a second length greater than the first length when the outer frame is in the second position relative to the inner frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/992,910, filed May 30, 2018, which is a continuation of InternationalApplication No. PCT/US2016/068680, filed on Dec. 27, 2016, which claimspriority to and the benefit of U.S. Provisional Patent Application No.62/271,606, entitled “Atrial Pocket Closures for Prosthetic HeartValves,” filed Dec. 28, 2015, each of the disclosures of which isincorporated herein by reference in its entirety.

This application is related to International Application No.PCT/US14/44047, filed Jun. 25, 2014, which is a continuation-in-part ofU.S. patent application Ser. No. 14/155,535, filed Jan. 15, 2014, andclaims priority to and the benefit of U.S. Provisional Application No.61/839,237, filed Jun. 25, 2013 and U.S. Provisional Application No.61/840,313, filed Jun. 27, 2013. The disclosures of the foregoingapplications are incorporated herein by reference in their entirety.

BACKGROUND

Prosthetic heart valves, including those for insertion intoatrioventricular valves (tricuspid and mitral valves) are susceptible tovarious problems, including problems with insufficient articulation andsealing of the valve within the native valve annulus, pulmonary edemadue to poor atrial drainage, perivalvular leaking around the installprosthetic valve, lack of a good fit for the prosthetic valve within thenative valve annulus, atrial tissue erosion, excess wear on the Nitinolstructures, interference with the aorta at the anterior side of themitral annulus, lack of customization, and thrombus formation, to name afew. Accordingly, there is a need for a prosthetic heart valve that canaddress some or all of these problems.

Moreover, there are a variety of different delivery approaches fordelivering and deploying a prosthetic heart valve into atrioventricularvalves and depending on the delivery approach the desired features andstructure of a prosthetic heart valve can vary. For example, intransvascular delivery of a prosthetic heart valve it is desirable tohave a prosthetic heart valve that can have an expanded configurationfor implantation within the heart and a collapsed or compressedconfiguration that has a sufficiently small outer perimeter or diameterto allow the prosthetic heart valve to be placed in a relatively smalldelivery catheter or sheath. In such embodiments of a prosthetic heartvalve, it is also desirable for features of the prosthetic heart valve,such as those described above, to be maintained.

SUMMARY

In some embodiments, a prosthetic heart valve can include an outer framecoupled to an inner frame such that the outer frame can be moved betweena first position relative to the inner frame and a second positionrelative to the inner frame in which the outer frame is invertedrelative to the inner frame. The inner frame and the outer frame definebetween them an annular space. In some embodiments, a pocket closurebounds the annular space to form a pocket in which thrombus can form andbe retained. The pocket closure can include a stretchable pocketcovering that can move from a first position in which the pocketcovering has a first length when the outer frame is in the firstposition relative to the inner frame and a second position in which thepocket covering has a second length greater than the first length whenthe outer frame is in the second position relative to the inner frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are a schematic perspective view and a sidecross-sectional view, respectively, of a prosthetic heart valve,according to an embodiment.

FIG. 2A is a schematic perspective view, of an inner valve assembly ofthe prosthetic heart valve of FIGS. 1A and 1B.

FIGS. 2B and 2C are schematic top views of the inner valve of FIG. 2A,shown in a first configuration and a second configuration, respectively.

FIGS. 3-5 are front, bottom, and top views, respectively, of aprosthetic heart valve according to another embodiment.

FIGS. 6A and 6B are schematic illustrations of a portion of a prostheticheart valve, according to an embodiment, shown in a first configurationand a second configuration, respectively.

FIGS. 6C and 6D are schematic illustrations of the portion of theprosthetic heart valve of FIGS. 6A and 6B, respectively, shown disposedwithin a delivery sheath.

FIGS. 7A and 7B are schematic illustrations of the portion of aprosthetic heart valve of FIGS. 6A and 6B, shown in the firstconfiguration and the second configuration, respectively.

FIG. 8A is a front view of a prosthetic heart valve according to anotherembodiment, shown in a first configuration.

FIG. 8B is a front view of the prosthetic heart valve of FIG. 8A, shownin a second configuration.

FIG. 9A is a front view of a prosthetic heart valve according to anotherembodiment, shown in a first configuration.

FIG. 9B is an enlarged view of encircled portion A of the prostheticheart valve of FIG. 9A.

FIG. 9C is a front view of the prosthetic heart valve of FIG. 9A, shownin a second configuration.

FIG. 10A is a cross-sectional side view of a prosthetic heart valve,according to another embodiment.

FIG. 10B is an enlarged view of encircled area A in FIG. 10A.

FIG. 10C is a perspective view of the prosthetic heart valve of FIG.10A.

FIG. 10D is a perspective view of a prosthetic heart valve, according toanother embodiment.

DETAILED DESCRIPTION

Prosthetic heart valves are described herein that include an outer framecoupled to an inner frame. The outer frame and the inner frame definebetween them an annular space, and a pocket closure bounds the annularspace to form a pocket in which thrombus can form and be retained. Insome embodiments, a prosthetic heart valve includes an outer framecoupled to an inner frame such that the outer frame can be moved betweena first position relative to the inner frame and a second positionrelative to the inner frame in which the outer frame is invertedrelative to the inner frame. In such an embodiment, the pocket closurecan include a stretchable pocket covering that can move from a firstposition in which the pocket covering has a first length when the outerframe is in the first position relative to the inner frame and a secondposition in which the pocket covering has a second length greater thanthe first length when the outer frame is in the second position relativeto the inner frame.

In some embodiments, prosthetic heart valves described herein can beconfigured to be moved to an inverted configuration for delivery of theprosthetic valve to within a heart of a patient. For example, in someembodiments, a prosthetic valve includes an outer frame that can beinverted relative to an inner frame when the prosthetic valve is in abiased expanded configuration. The prosthetic mitral valve can be formedwith, for example, a shape-memory material. After inverting the outerframe, the prosthetic valve can be inserted into a lumen of a deliverysheath such that the prosthetic valve is moved to a collapsedconfiguration.

The delivery sheath can be used to deliver an inverted prosthetic valveas described herein to within a patient's heart using a variety ofdifferent delivery approaches for delivering a prosthetic heart valve(e.g., prosthetic mitral valve) where the inverted prosthetic valvewould enter the heart through the atrium of the heart. For example, theprosthetic valves described herein can be delivered using a transfemoraldelivery approach as described in International Application No.PCT/US15/14572 (the '572 PCT application) incorporated by referenceabove or via a transatrial approach, such as described in U.S.Provisional Patent Application Ser. No. 62/220,704, entitled “Apparatusand Methods for Transatrial Delivery of Prosthetic Mitral Valve,” filedSep. 18, 2015 (“the '704 provisional application”), and described inU.S. patent application Ser. No. 15/265,221 filed Sep. 14, 2016 (the'221 application”), the entire disclosures of which are incorporatedherein by reference in their entirety. In another example, an invertedvalve as described herein could be delivered via a transjugularapproach, via the right atrium and through the atrial septum and intothe left atrium, as described in the '221 application. The prostheticvalves described herein can also be delivered apically if desired. Afterthe delivery sheath has been disposed within the left atrium of theheart, the prosthetic mitral valve is moved distally out of the deliverysheath such that the inverted outer frame reverts and the prostheticvalve assumes its biased expanded configuration. The prosthetic mitralvalve can then be positioned within a mitral annulus of the heart.

A schematic representation of a prosthetic heart valve 100 is shown inFIGS. 1A and 1B. Prosthetic heart valve 100 (also referred to as“prosthetic valve” or “valve”) is designed to replace a damaged ordiseased native heart valve such as a mitral valve. Valve 100 includesan outer frame assembly 110 and an inner valve assembly 140 that iscoupled to the outer frame assembly.

Although not separately shown in the schematic illustration of outerframe assembly 110 in FIGS. 1A and 1B, outer fame assembly 110 may beformed of an outer frame 120, and can be covered on all or a portion ofits outer face with an outer covering (not shown), and covered on all ora portion of its inner face by an inner covering (not shown). Anembodiment of a prosthetic valve showing the inner and outer coveringsis described below with respect to FIGS. 3-5. In some embodiments, theouter frame assembly 110 can include a covering on only an outer face oronly an inner face of the outer frame 120. In some embodiments, therecan be more than one layer of covering on the inner face and/or theouter face of the outer frame 120. The inner and outer coverings of theouter frame assembly 110 can completely cover the inner face and/orouter face of the outer frame 120 or can partially cover the inner faceand/or the outer face of the outer frame 120. In some embodiments, theouter frame assembly 110 may not include a covering on the inner face orthe outer face of the outer frame 120. For example, in some embodiments,the outer frame assembly 110 can include no material or covering on aninner face of the outer frame 120 and two layers or coverings disposedon an outer face of the outer frame 120. In such an embodiment, a firstlayer or covering can be, for example, a tissue that fully covers theouter face of the outer frame 120 and the outermost layer or coveringcan be a thin polyester that covers only a portion of the outer frame120. For example, the outermost covering can cover one or two rows ofcells of a cuff portion of the outer frame 120.

Outer frame 120 can provide several functions for prosthetic heart valve100, including serving as the primary structure, as an anchoringmechanism and/or an attachment point for a separate anchoring mechanismto anchor the valve to the native heart valve apparatus, a support tocarry inner valve assembly 140, and/or a seal to inhibit paravalvularleakage between prosthetic heart valve 100 and the native heart valveapparatus.

Outer frame 120 is preferably formed so that it can be deformed(compressed and/or expanded) and, when released, return to its original(undeformed) shape. To achieve this, outer frame 120 is preferablyformed of materials, such as metals or plastics, that have shape memoryproperties. With regards to metals, Nitinol® has been found to beespecially useful since it can be processed to be austenitic,martensitic or super elastic. Other shape memory alloys, such asCu—Zn—Al—Ni alloys, and Cu—Al—Ni alloys, may be used.

Outer frame 120 is preferably formed from a laser cut, thin-walled tubeof Nitinol®. The laser cuts form regular cutouts in the thin Nitinol®tube. The tube can be expanded radially, placed on a mold or mandrel ofthe desired shape, heated to the martensitic temperature, and quenched.The treatment of the frame in this manner will form an open latticeframe structure, and may have a flared end or cuff at the atrium endportion 116 of outer frame 120. Outer frame 120 thus has shape memoryproperties and will readily revert to the memory shape at the calibratedtemperature. Alternatively, outer frame 120 may be constructed frombraided wire or other suitable material.

Inner valve assembly 140 is shown schematically in more detail in FIGS.2A-2C. Inner valve assembly 140 can include an inner frame 150, an outercovering 160, and leaflets 170. In the simplified form shownschematically in FIG. 2A, inner frame 150 includes six axial posts orframe members that support outer covering 160 and leaflets 170. Leaflets170 are attached along three of the posts, shown as commissure posts 152in FIG. 2A, and outer covering 160 is attached to the other three posts,154 in FIG. 2A, and optionally to commissure posts 152. The outercovering 160 can be attached to an inner face of the inner frame 150 orto an outer face of the inner frame 150. As shown schematically in FIG.2A, each of outer covering 160 and leaflets 170 are formed ofapproximately rectangular sheets of material, which are joined togetherat their upper, or atrium end. The lower, ventricle end of outercovering 160 may be joined to the inner covering (not shown) of outerframe assembly 110 (not shown in FIG. 2A), and the lower, ventricle endof leaflets 170 may form free edges, though coupled to the lower ends ofcommissure posts 152. In some embodiments, the covering 160 and leaflets170 can be formed from a single rectangular sheet of material, thenfolded over and trimmed to the shape of the inner frame, stayingconnected at the top of the inner frame where the material is foldedover. In some embodiments, the covering 160 and/or the leaflets 170 canbe formed from material having a shape other than rectangular, such asfrom a semi-circular piece of material, or can be laser cut to the shapeof the inner frame.

As shown in FIGS. 2B and 2C, leaflets 170 are movable between a first oropen configuration (FIG. 2B), and a second or closed configuration (FIG.2C) in which the leaflets 170 coapt, or meet in sealing abutment.

At the lower, or ventricle end, leaflets 170 may have a smaller outerperimeter than outer covering 160. Thus, the free lower edges of theleaflets 170, between commissure posts 152 (each portion of leaflets 170between adjacent commissure posts being referred to as a “belly” ofleaflets 170) are spaced radially from the lower edge of outer covering160. This radial spacing facilitates movement of the leaflets from theopen position in FIG. 2B to the closed position in FIG. 2C, as thecounter flow of blood from the ventricle to the atrium during systolecan catch the free edges of the bellies and push the leaflets closed.

The outer covering and the inner covering of outer frame assembly 110,outer covering 160 and leaflets 170 may be formed of any suitablematerial, or combination of materials. In some embodiments, the outercovering and the inner covering of outer frame assembly 110, outercovering 160 and leaflets 170 may be formed of a tissue. In someembodiments, the tissue is optionally a biological tissue, such as achemically stabilized tissue from a heart valve of an animal, such as apig, or pericardial tissue of an animal, such as cow (bovinepericardium) or sheep (ovine pericardium) or pig (porcine pericardium)or horse (equine pericardium). Examples of suitable tissue include thatused in the products Duraguard®, Peri-Guard®, and Vascu-Guard®, allproducts currently used in surgical procedures, and which are marketedas being harvested generally from cattle less than 30 months old.Alternatively, valve leaflets 170 may optionally be made frompericardial tissue or small intestine submucosal tissue.

Synthetic materials, such as polyurethane or polytetrafluoroethylene,may also be used for valve leaflets 170. Where a thin, durable syntheticmaterial is contemplated, e.g. for the outer covering or the innercovering of outer frame assembly 110, synthetic polymer materials suchas, for example, expanded polytetrafluoroethylene or polyester mayoptionally be used. Other suitable materials may optionally includethermoplastic polycarbonate urethane, polyether urethane, segmentedpolyether urethane, silicone polyether urethane, silicone-polycarbonateurethane, and ultra-high molecular weight polyethylene. Additionalbiocompatible polymers may optionally include polyolefins, elastomers,polyethylene-glycols, polyethersulphones, polysulphones,polyvinylpyrrolidones, polyvinylchlorides, other fluoropolymers,silicone polyesters, siloxane polymers and/or oligomers, and/orpolylactones, and block co-polymers using the same.

In another embodiment, valve leaflets 170 may optionally have a surfacethat has been treated with (or reacted with) an anti-coagulant, such as,without limitation, immobilized heparin. Such currently availableheparinized polymers are known and available to a person of ordinaryskill in the art.

As shown in FIGS. 1A, 1B, and 2A, inner valve assembly 140 may besubstantially cylindrical, and outer frame assembly 110 may be tapered,extending from a smaller diameter (slightly larger than the outerdiameter of inner valve assembly 140) at a lower, ventricle portion 112(where it is coupled to inner valve assembly 140) to a larger diameter,atrium portion 116, with an intermediate diameter, annulus portion 114between the atrium and ventricle portions, 112 and 116, respectively.

A tapered annular space or pocket 185 (also referred to herein as“atrial pocket”) is thus formed between the outer surface of inner valveassembly 140 and the inner surface of outer frame assembly 110, open tothe atrium end of valve assembly 100. When valve assembly 100 isdisposed in the annulus of a native heart valve, blood from the atriumcan move in and out of pocket 185. The blood can clot, forming thrombus.To enhance clotting, ingrowth of tissue into the surfaces of valve 100,and produce other benefits, the pocket can be covered, or enclosed, by apocket closure 180 (also referred to as an “atrial pocket closure”).

Pocket closure 180 can be formed at least in part of any suitablematerial that is sufficiently porous to allow blood, includingparticularly red blood cells, to enter pocket 185, but is not so porousas to allow undesirably large thrombi to leave the pocket 185. Forexample, pocket closure 180 may be formed at least in part from a wovenor knit polyester fabric with apertures less than 160μ, and preferablybetween 90μ and 120μ. In some embodiments, the pocket closure 180 can beformed at least in part from a braided Nitinol material that has adesired porosity. In some embodiments, the pocket closure 180 can beformed at least in part from a braided tubular Nitinol material. It isnot necessary for the entirety of pocket closure 180 to be formed of thesame material, with the same porosity. For example, some portions ofpocket closure 180 may be formed of a less porous, or blood impermeable,material and other portions formed of material of the porosity rangenoted above. It is also contemplated that a portion of the outer frameassembly 110 or the inner valve assembly 140 may be formed with anaperture that communicates with pocket 180, covered by a closure formedof material having the desired porosity, thus providing another path bywhich blood may enter, but thrombi are prevented from leaving, atrialpocket 185.

The outer surface of inner valve assembly 110, and/or the inner surfaceof outer frame assembly 140, need not by circular in cross-section asshown schematically in FIGS. 1A and 1B, but may be of non-constantradius at a given location along the central axis of valve 100. Thus,pocket 185 may not be of constant cross-section, and may not becontinuous, but rather may be formed in two or more fluidicallyisolated, partially annular volumes. Similarly, pocket closure 180 neednot be shaped as a ring with constant width as shown schematically inFIGS. 1A and 1B, but rather can be a continuous ring of varying with, amore complicated continuous shape, or may be formed in multiple,discrete sections. In some embodiments, the pocket closure 180 can beformed as a tubular member defining an interior region.

Pocket closure 180 serves to trap and/or slow the flow of blood withinpocket 185, which can increase formation and retention of thrombus inpocket 185. It also promotes active in-growth of native tissue into theseveral coverings of prosthetic heart valve 100, further stabilizingvalve 100 in the native heart valve. The material forming the outercovering of inner valve assembly 140 can also be hardened or stiffened,providing better support for leaflets 170. Also, a mass of thrombusfilling pocket 185 can serve as potting for inner valve assembly 140,further stabilizing the valve assembly. Greater stability for innervalve assembly 140 can provide more reliable coaption of valve leaflets170, and thus more effective performance. The mass of thrombus can alsostabilize the outer frame assembly 110 after it has been installed in,and flexibly conformed to, the native valve apparatus. This can providea more effective seal between prosthetic heart valve 100 and the nativevalve apparatus, and reduce perivalvular leakage.

FIGS. 3-5 are front, bottom, and top views, respectively, of aprosthetic heart valve 200 according to an embodiment. Prosthetic heartvalve 200 (also referred to herein as “valve” or “prosthetic valve”) isdesigned to replace a damaged or diseased native heart valve such as amitral valve. Valve 200 includes an outer frame assembly 210 and aninner valve assembly 240 coupled to the outer frame assembly 210.

As shown, outer frame assembly 210 includes an outer frame 220, coveredon all or a portion of its outer face with an outer covering 230, andcovered on all or a portion of its inner face by an inner covering 232.Outer frame 220 can provide several functions for prosthetic heart valve200, including serving as the primary structure, as an anchoringmechanism and/or an attachment point for a separate anchoring mechanismto anchor the valve to the native heart valve apparatus, a support tocarry inner valve assembly 240, and/or a seal to inhibit paravalvularleakage between prosthetic heart valve 200 and the native heart valveapparatus.

Outer frame 220 has a biased expanded configuration and can bemanipulated and/or deformed (e.g., compressed and/or constrained) and,when released, return to its original unconstrained shape. To achievethis, outer frame 220 can be formed of materials, such as metals orplastics, that have shape memory properties. With regards to metals,Nitinol® has been found to be especially useful since it can beprocessed to be austenitic, martensitic or super elastic. Other shapememory alloys, such as Cu—Zn—Al—Ni alloys, and Cu—Al—Ni alloys, may alsobe used.

As best shown in FIG. 3, outer frame assembly 210 has an upper end(e.g., at the atrium portion 216), a lower end (e.g., at the ventricleportion 212), and a medial portion (e.g., at the annulus portion 214)therebetween. The upper end or atrium portion 216 (also referred to as“free end portion” or “open end portion”) defines an open end portion ofthe outer frame assembly 210. The medial or annulus portion 214 of theouter frame assembly 210 has a perimeter that is configured (e.g.,sized, shaped) to fit into an annulus of a native atrioventricularvalve. The upper end of the outer frame assembly 210 has a perimeterthat is larger than the perimeter of the medial portion. In someembodiments, the perimeter of the upper end of the outer frame assembly210 has a perimeter that is substantially larger than the perimeter ofthe medial portion. As shown best in FIG. 5, the upper end and themedial portion of the outer frame assembly 210 has a D-shapedcross-section. In this manner, the outer frame assembly 210 promotes asuitable fit into the annulus of the native atrioventricular valve.

Inner valve assembly 240 includes an inner frame 250, an outer covering260, and leaflets 270. As shown, the inner valve assembly 240 includesan upper portion having a periphery formed with multiple arches. Theinner frame 250 includes six axial posts or frame members that supportouter covering 260 and leaflets 270. Leaflets 270 are attached alongthree of the posts, shown as commissure posts 252 (best illustrated inFIG. 4), and outer covering 260 is attached to the other three posts,254 (best illustrated in FIG. 4), and optionally to commissure posts252. Each of outer covering 260 and leaflets 270 can be formed asdescribed above for outer covering 160 and leaflets 170. For example,each of outer covering 260 and leaflets 270 can be formed ofapproximately rectangular sheets of material, which are joined togetherat their upper, or atrium end. The lower, ventricle end of outercovering 260 may be joined to inner covering 232 of outer frame assembly210, and the lower, ventricle end of leaflets 270 may form free edges275, though coupled to the lower ends of commissure posts 252.

Although inner valve assembly 240 is shown as having three leaflets, inother embodiments, an inner valve assembly can include any suitablenumber of leaflets. The leaflets 270 are movable between an openconfiguration and a closed configuration in which the leaflets 270coapt, or meet in a sealing abutment.

Outer covering 230 of the outer frame assembly 210 and inner covering232 of outer frame assembly 210, outer covering 260 of the inner valveassembly 240 and leaflets 270 of the inner valve assembly 240 may beformed of any suitable material, or combination of materials, such asthose discussed above for valve 100. In this embodiment, the innercovering 232 of the outer frame assembly 210, the outer covering 260 ofthe inner valve assembly 240, and the leaflets 270 of the inner valveassembly 240 are formed, at least in part, of porcine pericardium.Moreover, in this embodiment, the outer covering 230 of the outer frameassembly 210 is formed, at least in part, of polyester.

Prosthetic valve 200 also defines a tapered annular space or pocket (notshown) formed between the outer surface of inner valve assembly 240 andthe inner surface of outer frame assembly 210, open to the atrium end ofvalve assembly 200. As shown, a pocket closure or covering 280 (thepocket being disposed below pocket closure 280 in the top view of FIG.5) is coupled along the periphery of the upper end of the inner valveassembly 240 and also to the outer valve assembly 210. In someembodiments, the pocket closure 280, or a portion thereof, can becoupled along any suitable portion of the inner valve assembly 240.

As discussed above, pocket closure 280 can be formed at least in part ofany suitable material that is sufficiently porous to allow blood,including particularly red blood cells, to enter the pocket, but is notso porous as to allow undesirably large thrombi to leave the pocket. Inthis embodiment, pocket closure 280 is formed entirely of knit polyester(i.e., PET warp knit fabric) having apertures of about 90-120 microns.In some embodiments, a pocket closure can include apertures less thanabout 160 microns.

As previously described, in some embodiments, a prosthetic heart valve,such as a prosthetic mitral valve, can be configured to be moved to aninverted configuration for delivery of the prosthetic valve to within aheart of a patient. For example, the outer frame can be moved orinverted relative to the inner frame of the valve. After inverting theouter frame, the prosthetic valve can be inserted into a lumen of adelivery sheath such that the prosthetic valve is moved to a collapsedconfiguration for delivery of the valve o the heart. FIGS. 6A-6D andFIGS. 7A and 7B illustrate schematically an embodiment of a prostheticvalve that can be moved between a biased expanded configuration for useand an inverted configuration for delivery to a heart.

FIGS. 6A and 6B are schematic illustrations of a portion of a prostheticheart valve 300, according to an embodiment, shown in a firstconfiguration and a second configuration respectively, and FIGS. 6C and6D illustrate the portions of the prosthetic heart valve 300 of FIGS. 6Aand 6B, respectively, shown disposed within a lumen of a delivery sheath326. FIGS. 7A and 7B illustrate a portion of the prosthetic heart valve300 of FIGS. 6A and 6B, respectively, and show length dimensions for theprosthetic heart valve in each of the first configuration and the secondconfiguration. The prosthetic heart valve 300 (also referred to hereinas “prosthetic valve” or “valve”) can be, for example, a prostheticmitral valve. The valve 300 includes an outer frame 320 and an innerframe 350. The outer frame 320 and the inner frame 350 are each formedas a tubular structure. The outer frame 320 and the inner frame 350 canbe coupled together at multiple coupling joints 346 disposed about aperimeter of the inner frame 350 and a perimeter of the outer frame 320as described in more detail below. The valve 300 can also include otherfeatures, such as those described above with respect to FIGS. 1-5. Forexample, the valve 300 can include an outer frame assembly, includingthe outer frame 320, and an inner valve assembly that includes the innerframe 350, that can be formed or configured the same as or similar tothe outer frame assemblies and inner valve assemblies described abovewith respect to FIGS. 1-5. For illustration purposes, only the innerframe 350 and the outer frame 320 are discussed with respect to FIGS.6A-7B. The various characteristics and features of valve 300 describedwith respect to FIGS. 6A-7B can apply to any of the prosthetic valvesdescribed here.

The outer frame 320 is configured to have a biased expanded orundeformed shape and can be manipulated and/or deformed (e.g.,compressed or constrained) and, when released, return to its original(expanded or undeformed) shape. For example, the outer frame 320 can beformed of materials, such as metals or plastics, that have shape memoryproperties. With regards to metals, Nitinol® has been found to beespecially useful since it can be processed to be austenitic,martensitic or super elastic. Other shape memory alloys, such asCu—Zn—Al—Ni alloys, and Cu—Al—Ni alloys, may also be used. The innerframe 350 can be formed from a laser-cut tube of Nitinol®. The innerframe 350 can also have a biased expanded or undeformed shape and can bemanipulated and/or deformed (e.g., compressed and/or constrained) and,when released, return to its original (expanded or undeformed) shape.Further details regarding the inner frame 350 and the outer frame 320are described below and with respect to valve 200 and FIGS. 3-5.

The valve 300 can be delivered and deployed within a left atrium of aheart using a variety of different delivery approaches including, forexample, a transfemoral delivery approach, as described in the '572 PCTapplication, or a transatrial approach, as described in the '704provisional application and the '221 application, or a transjugularapproach as described, for example, in the '221 application. Asdescribed above, in some situations, such as when delivering aprosthetic valve to the heart via a transfemoral, transjugular ortransatrial approach, because of the smaller size of the lumen of thedelivery sheath, the size of the prosthetic valve during delivery shouldbe sized accordingly. Thus, it is desirable to have a prosthetic valvethat can be reconfigured between a biased expanded configuration forimplantation in the heart (e.g., within a native mitral annulus) and adelivery configuration that has a smaller outer perimeter or profile toallow for delivery within the lumen of the delivery sheath. Theprosthetic valve 300 and the embodiments of a prosthetic valve describedherein can be constructed and formed to achieve these desired functionsand characteristics.

More specifically, the valve 300 can have a biased expandedconfiguration (as shown in FIGS. 6A and 7A), an inverted configuration(as shown in FIGS. 6B and 7B), and a compressed or collapsedconfiguration (as shown in FIGS. 6C and 6D). The expanded configurationallows the valve 300 to function when implanted within the heart. Thevalve 300 can be moved to the inverted configuration and the compressedor collapsed configuration for delivery of the valve 300 to the heart ofa patient.

To enable the valve 300 to be moved to the inverted configuration, theouter frame 320 can be coupled to the inner frame 350 in such a mannerto allow the outer frame 320 to move relative to the inner frame 350.More specifically, the coupling joints 346 can couple the outer frame320 to the inner frame 350 in such a manner to allow the outer frame 320to be moved relative to the inner frame 350. For example, in someembodiments, the coupling joints 346 can be configured to allow theouter frame 320 to rotate about the coupling joint 346 relative to theinner frame 350. In some embodiments, coupling joints can provide apivotal coupling between the outer frame 320 and the inner frame 350. Insome embodiments, the coupling joints can provide a flexible attachmentbetween the outer frame 320 and the inner frame 350. The coupling joints346 can be a variety of different types and configurations as describedherein with reference to the various embodiments of a prosthetic valve.For example, the coupling joints 146 can include a living hinge, aflexible member, sutures, a suture wrapped through an opening, a pin ortab inserted through an opening or any combinations thereof.

To move the valve 300 from the expanded configuration (FIG. 6A) to theinverted configuration (FIG. 6B), the outer frame 320 is moved to aprolapsed or inverted configuration relative to the inner frame 350, asshown in FIGS. 6B, 6D and 7B, by moving (e.g., rotating, pivoting,flexing) the outer frame 320 about the coupling joints 346. The elasticor superelastic structure of outer frame 320 of valve 300 also allowsthe outer frame 320 to be moved to, and disposed in, the prolapsed orinverted configuration relative to the inner frame 350. To move theouter frame 320 to the inverted configuration relative to the innerframe 350, the outer frame 320 is folded or inverted distally (to theright in FIG. 6B) relative to the inner frame 350 via the couplingjoints 346. As shown in FIGS. 6A and 7A, the outer frame 320 is in afirst position relative to the inner frame 350 prior to being invertedin which an open or free end portion 316 (also referred to the atriumportion 316 of the outer frame 320) is disposed proximally or to theleft of the coupling joints 346 and in the same direction as a free endportion 347 (also referred to as a second end portion of the innerframe) of the inner frame 350. When the outer frame 320 is moved to aninverted configuration (i.e., second positon relative to the inner frame350), the free end portion 316 is disposed distally of the couplingjoints 346 (or to the right in FIGS. 6B and 7B) and in an oppositedirection as the free end portion 347 of the inner frame 350. Saidanother way, when the valve 300 is in a biased expanded configuration(e.g., FIG. 6A), the coupling joints 346 are disposed between a firstend portion 344 (also referred to as a tether coupling portion) of theinner frame 350 and the free end portion 316 of the outer frame 320.When the valve 300 is in the inverted configuration (e.g., FIG. 6B)(i.e., the outer frame 320 has been moved to an inverted configurationor position), the coupling joints 346 are disposed between the free endportion or second end portion 347 of the inner frame 350 and the freeend portion 316 of the outer frame 320.

When in the inverted configuration, an overall length of the valve 300is increased, but a length of the inner frame 350 and a length of theouter frame 320 remains the same (or substantially the same). Forexample, as shown in FIGS. 7A and 7B an overall length L1 of the valve300 in the biased expanded configuration (prior to being inverted asshown in FIG. 7A) is less than the overall length L2 of the valve 300when in the inverted configuration (FIG. 7B). A length Li of the innerframe 350 and a length Lo of the outer frame 320 is substantially thesame (or the same) when the valve 300 is in both the biased expandedconfiguration and the inverted configuration. In addition, in someinstances, depending on the specific configuration of the outer frame,an overall outer perimeter or outer diameter of the valve 300 can besmaller when the valve 300 is in the inverted configuration.

With the valve 300 in the inverted configuration, the valve 300 can beplaced within a lumen of the delivery sheath 326 for delivery of thevalve 300 to the left atrium of the heart, as shown in FIG. 6D. Whenplaced within the lumen of the delivery sheath 326, the valve 300 ismoved to the collapsed or compressed configuration in which the outerdiameter or outer perimeter of the valve 300 is reduced. Because thevalve 300 is in the inverted configuration, the valve 300 is able to beplaced within a smaller delivery sheath 326 than would otherwise bepossible. For example, for comparison purposes, FIG. 6C illustrates thevalve 300 placed within a lumen of a delivery sheath 326′ where thevalve 300 has not been moved to an inverted configuration prior to beingdisposed within the delivery sheath 326′. As shown in FIG. 6C, an outerdiameter of the valve 300 is reduced, but not to as small of a diameteras for the valve 100 when placed in a delivery sheath 326 when in theinverted configuration. Thus, in FIG. 6C, the valve 300 has an overallouter perimeter or outer diameter D1 and in FIG. 6D, the valve 300 hasan overall outer perimeter or outer diameter D2, which is less than D1.

Thus, by disposing the outer frame 320 in the inverted configuration,the valve 300 can be collapsed into a smaller overall diameter, i.e.placed in a smaller diameter delivery sheath 326, than would be possibleif the valve 300 were merely collapsed radially. This is because whenthe valve is in the biased expanded configuration, the inner frame 350is nested within an interior of the outer frame 320, and thus the outerframe 320 must be collapsed around the inner frame 350. In someembodiments, the inner frame 350 and the outer frame are disposedconcentrically. Whereas in the inverted configuration, the inner frame350 and the outer frame 320 are arranged axially with respect to eachother (i.e., the inner frame is not nested within the outer frame 350),such that the outer frame 320 can be collapsed without needing toaccommodate all of the structure of the inner frame 350 inside it. Inother words, with the inner frame 350 disposed mostly inside or nestedwithin the outer frame 320, the layers or bulk of the frame structurescannot be compressed to as small a diameter. In addition, if the framesare nested, the structure is less flexible, and therefore, more force isneeded to bend the valve, e.g. to pass through tortuous vasculature orto make tight turn in the left atrium after passing through the atrialseptum to be properly oriented for insertion into the mitral valveannulus.

FIGS. 8A and 8B illustrate another embodiment of a prosthetic heartvalve that can be delivered and deployed within a left atrium of a heartusing a variety of different delivery approaches and which can be movedbetween an expanded configuration and an inverted configuration asdescribed above for valve 300. The prosthetic heart valve 400 (alsoreferred to herein as “prosthetic valve” or “valve”) can be, forexample, a prosthetic mitral valve. The valve 400 includes an outerframe assembly including an outer frame 420 and an inner valve assemblyincluding an inner frame 450. The outer frame 420 and the inner frame450 are each formed as a tubular structure. The valve 400 can alsoinclude other features, such as those described above with respect toFIGS. 1A-7D. For illustration purposes, only the inner frame 450 and theouter frame 420 are discussed with respect to FIGS. 8A-8B. It should beunderstood that the various characteristics and features of the valvesdescribed above with respect to FIGS. 1A-7D can apply to valve 400.

The outer frame 420 and the inner frame 450 can be coupled together atmultiple coupling joints 446 disposed about a perimeter of the innerframe 450 and a perimeter of the outer frame 420 as described above forvalve 300. The coupling joints 446 can allow the outer frame 420 to bemoved relative to the inner frame 450 as described above for valve 300.For example, the outer frame 420 can be moved between a first position(FIG. 8A) relative to the inner frame 450 to a second position (FIG. 8B)relative to the inner frame 450. In the first position, an open free endportion 416 of the outer frame 420 is disposed in the same direction asan open free end portion 447 of the inner frame 450 (see FIG. 8A). Inthe second position, the outer frame 420 is inverted relative to theinner frame 450 such that the free end portion 416 of the outer frame420 is now disposed in an opposite direction as the free end portion 447of the inner frame 450 (see FIG. 8B).

As described above for valves 100 and 200, a tapered annular space orpocket 485 (also referred to as “atrial pocket”) is formed between anouter surface of the inner valve assembly and an inner surface of theouter frame assembly, open to an atrium end of valve 400. When valve 400is disposed in the annulus of a native heart valve, blood from theatrium can move in and out of pocket 485. The blood can clot, formingthrombus. To enhance clotting, ingrowth of tissue into the surfaces ofvalve 400, and produce other benefits, the pocket 485 can be covered, orenclosed, by a pocket closure 480 (also referred to as an “atrial pocketclosure”). The pocket closure 480 is coupled about a perimeter of theinner frame 450 and a perimeter of the outer frame 420 so as toclose-out the pocket 485 at the atrial end of the valve 400. As shown inFIGS. 8A and 8B the pocket closure 480 is coupled to the inner frame 450at coupling portion 482 and to outer frame 420 at coupling portion 483.The pocket closure 480 can be formed of one continuous segment orportion of material or can be formed with two or more portions orsegments that are coupled together. For example, in some embodiments,the pocket closure 480 can be formed of three portions or segments thatare sewn together with sutures or another suitable coupling method.

As described above, pocket closure 480 can be formed at least in part ofany suitable material that is sufficiently porous to allow blood,including particularly red blood cells, to enter the pocket 485, but isnot so porous as to allow undesirably large thrombi to leave the pocket485. For example, pocket closure 480 may be formed at least in part froma material with apertures less than 160μ, and preferably between 90μ and120μ. In this embodiment, the pocket closure 480 can be formed at leastin part from a braided Nitinol material (or a braided tubular Nitinolmaterial) that has the desired porosity. The braided Nitinol materialalso provides a desired stretchability, flexibility or deformability toaccommodate movement of the outer frame 420 between the first positonrelative to the inner frame 450 and the second inverted positionrelative to the inner frame 450. For example, the braided Nitinolmaterial can have shape memory properties that allow the pocket closure480 to be deformed and/or stretched and then revert back to an originalshape or configuration when released.

As shown in FIG. 8A, when the outer frame 420 is in the first positionrelative to the inner frame 450, the pocket closure 480 is disposed in afirst configuration. As shown in FIG. 8B, when the outer frame 420 is inthe second position (i.e., inverted) relative to the inner frame 450,the pocket closure 480 is disposed in a second configuration. Morespecifically, when the outer frame 420 is moved to the second positionin which the outer frame 420 is inverted relative to the inner frame420, the material and structure of the pocket closure 480 enables thepocket closure 480 to stretch with the outer frame 420 as shown in FIG.8B. In other words, as shown in FIG. 8B, the pocket closure 480 isstretched or elongated between where it is coupled to the inner frame(i.e., coupling portion 482) and where it is coupled to the outer frame(i.e., coupling portion 483) to a length greater than when the outerframe 420 is in the first positon as shown in FIG. 8A. When the outerframe 420 is moved back to the first position relative to the innerframe 450, the pocket closure 480 can assume its first configuration asshown in FIG. 8A.

FIGS. 9A and 9B illustrate another embodiment of a prosthetic heartvalve that includes a pocket closure that can accommodate the valvebeing moved between an expanded configuration and an invertedconfiguration for delivery and deployment of the valve within a leftatrium of a heart. The prosthetic heart valve 500 (also referred toherein as “prosthetic valve” or “valve”) can be, for example, aprosthetic mitral valve. The valve 500 includes an outer valve assemblyincluding an outer frame 520 and an inner valve assembly including aninner frame 550. The outer frame 520 and the inner frame 550 are eachformed as a tubular structure. The valve 500 can also include otherfeatures, such as those described above with respect to FIGS. 1A-7D. Forillustration purposes, only the inner frame 550 and the outer frame 520are discussed with respect to FIGS. 8A-8B. It should be understood thatthe various characteristics and features of the valves described abovewith respect to FIGS. 1A-7D can apply to valve 500.

As with the previous embodiments, the outer frame 520 and the innerframe 550 can be coupled together at multiple coupling joints 546disposed about a perimeter of the inner frame 550 and a perimeter of theouter frame 520 as described above for valve 300. The coupling joints546 can allow the outer frame 520 to be moved relative to the innerframe 550 as described above for valve 300. For example, the outer frame520 can be moved between a first position (FIG. 9A) relative to theinner frame 550 to a second position (FIG. 9B) relative to the innerframe 550. In the first position, an open free end portion 516 of theouter frame 520 is disposed in the same direction as an open free endportion 547 of the inner frame 550 (see FIG. 9A). In the secondposition, the outer frame 520 is inverted relative to the inner frame550 such that the free end portion 516 of the outer frame 520 is nowdisposed in an opposite direction as the free end portion 547 of theinner frame 550 (see FIG. 9B).

As described above for valves 100 and 200, a tapered annular space orpocket 585 (also referred to as “atrial pocket”) is formed between anouter surface of the inner valve assembly and an inner surface of theouter frame assembly, open to an atrium end of valve 500. When valve 500is disposed in the annulus of a native heart valve, blood from theatrium can move in and out of pocket 585. The blood can clot, formingthrombus. To enhance clotting, ingrowth of tissue into the surfaces ofvalve 500, and produce other benefits, the pocket 585 can be covered, orenclosed, by a pocket closure 580 (also referred to as an “atrial pocketclosure”).

In this embodiment, the pocket closure 580 includes a first portion 584coupled to a second portion 586. As shown in the detail view of FIG. 9B,the first portion 584 includes a first end coupled to the outer frame520 at a coupling joint 587, and a second end coupled to the secondportion 586 at a coupling joint 588. The second portion 586 has a firstend coupled to the first portion 584 at the coupling joint 588 and asecond end coupled to the outer frame 520 at a coupling joint 589. Thus,in this embodiment, the pocket closure 580 is coupled only to the outerframe 520. The pocket closure 580 can close-out the pocket at the atrialend of the valve 500. The first portion 584 and the second portion 586of the pocket closure 580 can each be formed as one continuous segmentor portion of material or can be formed with two or more portions orsegments that are coupled together with for example, sutures or anothersuitable coupling method.

As described above, pocket closure 580 can be formed at least in part ofany suitable material that is sufficiently porous to allow blood,including particularly red blood cells, to enter the pocket 585, but isnot so porous as to allow undesirably large thrombi to leave the pocket585. For example, pocket closure 580 may be formed at least in part froma material with apertures less than 160μ, and preferably between 90μ and120μ. In this embodiment, the first portion 584 of pocket closure 580can be formed at least in part from a woven or knit polyester fabricwith apertures less than 160μ, and preferably between 90μ and 120μ. Thesecond portion 586 of pocket closure 580 can be formed with a tubularbraided Nitinol material as described above for valve 400 that canprovide a desired stretchability or flexibility or deformability toaccommodate the outer frame 520 moving between the first positonrelative to the inner frame 550 and the second inverted positionrelative to the inner frame 550.

As shown in FIG. 9A, when the outer frame 520 is in the first positionrelative to the inner frame 550, the pocket closure 580 is disposed in afirst configuration. As shown in FIG. 9B, when the outer frame 520 is inthe second position (i.e., inverted) relative to the inner frame 550,the pocket closure 580 is disposed in a second configuration. Morespecifically, when the outer frame 520 is moved to the second positionin which the outer frame 520 is inverted relative to the inner frame520, the material and structure of the second portion 586 of the pocketclosure 580 enables the pocket closure 580 to stretch with the outerframe 520 as shown in FIG. 9B. In other words, as shown in FIG. 9B, thesecond portion 586 of pocket closure 580 can stretch or elongate betweenwhere it is coupled to the first portion 584 of the pocket closure 580(i.e., coupling joint 588) and where it is coupled to the outer frame520 (i.e., coupling portion 589) to a length greater than when the outerframe 520 is in the first positon as shown in FIG. 9A. The first portion584 of pocket closure 580 does not stretch when the outer frame 520 ismoved to the second position (i.e., inverted) relative to the innerframe 550. When the outer frame 520 is moved back to the first positionrelative to the inner frame 550, the pocket closure 580 can assume itsfirst configuration as shown in FIG. 9A.

In some embodiments of a prosthetic heart valve, an additional materiallayer can be attached to the inner frame in addition to the outercovering described above for previous embodiments (e.g., outer covering160). The additional material layer can be attached to an inner face oran outer face of the inner frame of the valve. For example, theadditional material layer can be attached to an inner face of the innerframe and outside of the leaflets of the valve. In other words, theouter covering can be disposed between the leaflets and the additionalmaterial layer, with all three components (leaflets, outer covering andadditional material layer) disposed on an inner side of the inner frameof the valve. The additional material layer may be desirable to preventpossible billowing of the belly area of the leaflet. Such billowing canoccur, for example, when backpressure that can cause the leaflets toclose also applies pressure to the belly area of the leaflets,potentially causing them to bulge out into the pocket area towards theouter frame. The additional material layer can be composed of a varietyof different materials. FIGS. 10A-10C illustrate a prosthetic heartvalve 600 that includes such a material layer 625. In this embodiment,the material layer 625 is disposed as a cylinder that covers an innerframe 650 from a base 622 of the inner frame 650 to a peak or atrium end624 of the inner frame 650. As shown in FIGS. 10A and 10B, the valve 600includes leaflets 670. As shown in FIG. 10C, the cylindrically disposedmaterial layer 625 bridges the peaks 624 of the frame 650. In analternative embodiment, the material layer can be configured to followthe shape of the inner frame as shown in FIG. 10D. In this embodiment, avalve 600′ includes a material layer 625′ that substantially follows orconforms to the shape of the inner frame 650. In other words, thematerial layer 625′ spans between frame portions of the inner frame 650.In some embodiments, the material layers 625, 625′ can be, for example,a polyester material.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation, and as such, various changes in form and/or detail may bemade. Any portion of the apparatus and/or methods described herein maybe combined in any suitable combination, unless explicitly expressedotherwise. The embodiments described herein can include variouscombinations and/or sub-combinations of the functions, components,and/or features of the different embodiments described.

Where methods described above indicate certain events occurring incertain order, the ordering of certain events and/or flow patterns maybe modified. Additionally, certain events may be performed concurrentlyin parallel processes when possible, as well as performed sequentially.

What is claimed is:
 1. A method of implanting a prosthetic heart valveinto a native valve annulus, the method comprising: disposing theprosthetic heart valve within a delivery device in a collapsed deliverycondition, the prosthetic heart valve including an inner frame having anopen end portion, and an outer frame coupled to the inner frame andhaving an open end portion, the outer frame being inverted relative tothe inner frame when the prosthetic heart valve is in the collapseddelivery condition so that the open end of the outer frame and the openend of the inner frame point in opposite directions; delivering thedelivery device to the native valve annulus; ejecting the prostheticheart valve from the delivery device; transitioning the prosthetic heartvalve from the collapsed delivery condition to an expanded condition,the outer frame reverting relative to the inner frame during thetransitioning so that the open end of the outer frame and the open endof the inner frame point in a same direction; and positioning theprosthetic heart valve in the native valve annulus, wherein in theexpanded condition of the prosthetic heart valve, an annular space isdefined between a portion of the inner frame and a portion of the outerframe, the annular space being open toward the open end portion of theouter frame and the open end portion of the inner frame when theprosthetic heart valve is in the expanded condition, a pocket coveringbeing coupled to the inner frame and coupled to the outer frame suchthat the annular space is covered by the pocket covering between theopen end portion of the inner frame and the open end portion of theouter frame when the prosthetic heart valve is in the expandedcondition.
 2. The method of claim 1, wherein the pocket covering iscoupled to the inner frame and coupled to the outer frame when theprosthetic heart valve is in the collapsed delivery condition.
 3. Themethod of claim 2, wherein the pocket covering is a stretchable pocketcovering.
 4. The method of claim 3, wherein the stretchable pocketcovering has a first length when the prosthetic heart valve is in thecollapsed delivery condition, and the stretchable pocket coveringtransitions to a second length smaller than the first length when theprosthetic heart valve transitions from the collapsed delivery conditionto the expanded condition.
 5. The method of claim 3, wherein thestretchable pocket covering, the inner frame, and the outer framecollectively define a pocket in which thrombus can form and be retainedwhen the prosthetic heart valve is in the expanded condition anddisposed within the native valve annulus of a patient.
 6. The method ofclaim 5, wherein the pocket covering is formed of a material having aporosity that is sufficiently large to allow red blood cells to passthrough the pocket closure into the pocket and that is sufficientlysmall to prevent thrombus formed from the red blood cells to passthrough the pocket closure from the pocket.
 7. The method of claim 1,wherein the pocket covering is formed of a braided Nitinol material. 8.The method of claim 1, wherein the prosthetic heart valve includes anouter covering disposed on the inner frame, a plurality of prostheticleaflets disposed within an interior of the inner frame, and a materiallayer disposed over the outer covering and conforming to the shape ofthe inner frame, the material layer configured to prevent billowing of abelly area of the leaflets into the annular space.
 9. The method ofclaim 1, wherein the outer frame is coupled to the inner frame atmultiple coupling joints, the inner frame including a tether couplingportion opposite the open end portion of the inner frame, the couplingjoints being disposed between the open end portion of the outer frameand the tether coupling portion of the inner frame when the prostheticheart valve is in the expanded condition, the coupling joints beingdisposed between the open end portion of the inner frame and the openend portion of the outer frame when the prosthetic heart valve is in thecollapsed delivery condition.
 10. The method of claim 1, wherein thepocket covering has a first portion coupled to a second portion, thefirst portion being coupled to the outer frame at a first couplingjoint, the second portion being coupled to the outer frame at a secondcoupling joint.
 11. The method of claim 10, wherein the pocket coveringis configured to move between a first configuration in which the secondportion of the pocket covering has a first length and a secondconfiguration in which the second portion of the pocket covering has asecond length smaller than the first length as the prosthetic heartvalve transitions from the collapsed delivery condition to the expandedcondition.
 12. The method of claim 10, wherein the pocket covering, theinner frame, and the outer frame collectively define a pocket in whichthrombus can form and be retained when the prosthetic heart valve is inthe expanded condition and disposed within the native valve annulus of apatient.
 13. The method of claim 12, wherein the pocket closure isformed of a material having a porosity that is sufficiently large toallow red blood cells to pass through the pocket closure into the pocketand that is sufficiently small to prevent thrombus formed from the redblood cells to pass through the pocket closure from the pocket.
 14. Themethod of claim 10, wherein the pocket covering is formed of a shapememory material configured to be to be moved from a biased configurationto an elongated configuration and back to the biased configuration. 15.The method of claim 1, wherein the pocket covering, the inner frame, andthe outer frame collectively define a pocket in which thrombus can formand be retained when the prosthetic heart valve is in the expandedcondition and disposed within the native valve annulus of a patient. 16.The method of claim 15, wherein the pocket closure is formed of amaterial having a porosity that is sufficiently large to allow red bloodcells to pass through the pocket closure into the pocket and that issufficiently small to prevent thrombus formed from the red blood cellsto pass through the pocket closure from the pocket.
 17. The method ofclaim 1, wherein ejecting the prosthetic heart valve from the deliverydevice includes ejecting the inner frame from the delivery device afterthe outer frame is ejected from the delivery device.
 18. The method ofclaim 17, wherein the inner frame retains a same orientation relative tothe delivery device as the inner frame is ejected from the deliverydevice.
 19. The method of claim 18, wherein the outer frame reversesorientation relative to the delivery device as the outer frame isejected from the delivery device.
 20. The method of claim 1, whereindelivering the delivery device to the native valve annulus includespassing the delivery device from a right atrium to a left atrium throughan atrial septum disposed between the right atrium and the left atrium.